EFFECT OF FINITE WIDTH ON DYNAMIC DEFLECTIONS OF PAVEMENTS. INTERIM REPORT
A highway has a finite width in its transverse direction, and the existence of variation in material properties between the road and the surrounding soil is not uncommon. A three-dimensional elastodynamic solution is presented to take into account the variation of material properties in the soil-pavement system by using the Fourier superposition technique. The pavement, base and subgrade are represented by a finite-element core region. An expansion technique is used to simulate the infinite lateral soil region. A viscous boundary is implemented for a half space condition. The stiffness matrices and point load and disk load vectors are obtained in the frequency-wave number domain. Parametric studies of the soil-pavement formulation are conducted to assess the accuracy of the results. An investigation of the effects of the lateral boundary on the pavement deflections measured by various nondestructive testing techniques is presented. The Dynaflect, the Falling Weight Deflectometer (FWD), and the Spectral-Analysis-of-Surface-Waves (SASW) methods are simulated on three typical in-service pavement sections. The results of the Dynaflect tests indicate that the effects of the lateral boundary on the measured deflections are directly related to: (a) the loading position with respect to the edge of the pavement; (b) the thickness of the surface layer; (c) the lateral stiffness contrast between the road and the surrounding soil; (d) the height of the ramp, if the test is performed on a ramp. A closer loading position, a larger value of the thickness, a higher contrast, and a larger value of the ramp height will result in a larger influence on the deflections. The lateral boundary also has a differential influence on different stations which will, in turn, change the shape of the deflection basins. The existence of retaining walls is important, especially for the "high" ramp. Similar conclusions are reached for the FWD test simulations. The results of the SASW tests indicate that some fluctuations may occur in the dispersion curve because of the reflected body waves due to the abrupt change in the stiffness at the horizontal interfaces between layers. The existence of the lateral boundary causes additional fluctuations, particularly for long wavelengths.
- Research study title: Non-Destructive Test Procedures for Analyzing the Structural Conditions of Pavements.
University of Texas, AustinCenter for Transportation Research, 3208 Red River Street
Austin, TX United States 78705
Austin, TX United States 78763
Washington, DC United States 20590
- Kang, Y V
- Roesset, J M
- Stokoe II, K H
- Publication Date: 1991-1
- Features: Appendices; Figures; References; Tables;
- Pagination: 128 p.
- TRT Terms: Accuracy; Deflection; Dynaflect; Falling weight deflectometers; Finite element method; Fourier transforms; Pavements; Rayleigh waves; Spectrum analysis
- Candidate Terms: Spectral analysis of surface waves
- Uncontrolled Terms: Soil-pavement system
- Old TRIS Terms: Dynaflect deflections; Finite width; Pavement deflection
- Subject Areas: Design; Highways; Pavements; I22: Design of Pavements, Railways and Guideways; I23: Properties of Road Surfaces;
- Accession Number: 00625035
- Record Type: Publication
- Report/Paper Numbers: FHWA/TX-91+1123-6, Res Rept 1123-6, CTR 2/3-18-87/0-1123-6
- Contract Numbers: Study 2/3-18-87/9-1123
- Files: TRIS, USDOT, STATEDOT
- Created Date: Oct 5 1996 12:00AM